Process for carbonizing coal



JuneI 24, 1930. w. E. TRENT PROCESS FOR CARBONIZING COAL Filed Feb. 27,1925 i 4 H 7- l@ E E i m m .w ,C E F y@ MEW M E AOp A.

Patented June 24, 1930 UNITED STATES WALTER EDWIN TREN'I, 0F NEW' YORK,N. Y., ASSIG-NOR TO TRENT PROCESS CORPO- RATION, OF NEW YORK, N. Y., ACORPORATION F DELAWARE PRocEss Fon CARBONIZING coAL Application medFebruary 27, 1925. serian No. 12,129.

The invention relates to a process for carbonizing coal and coal and oilmixtures to produce carbonized or coked products of substantially thesame dimensions as the ygreen preformed fuel masses.

' product will be free of substantial swelling or shrinkage, and,therefore, of dimensions substantially the same as the dimensions of theoriginal green mass from which the car-l bonized fuel is produced.

My invention, therefore, broadly comprehends a two-'stage treatment inthe carbonization of coals, in which the coal in the first 'stage ispartially carbonized under a low temperature in the presence of alimited amount of oxygen and in the secondstage ,is 'heated to a hightemperature in an atmosphere substantially free of oxygen to 4form thecarbonized products herein referred to.

ln the accompanying draWings,-

Figure 1 is a View of an apparatus capable of carrying out thefirst-stage treatment; and

2 is a view of the apparatus used in the second-stage treatment of thecoal.

Fig. 3 is a View of a slightly modiied form of pan.

'Referring noW more particularly to the drawings, wherein like referencecharacters indicate corresponding parts, the numeral 1 designates thecarbonizing furnace used for the purpose of heating the material to alow temperature in the presence of oxygen. This furnace has a sprocket 2at one end and is also provided with gas outlet pipes.

3 leading to a header 4. A sprocket 5 is disposed outside of the furnaceand this sprocket together with the sprocket 2 receives the endlessconveyor 6 l carrying a series of pans 7 each havin a false bottom 8,providing a receiver 9 for heat storage elements to be later described.The pans move Vthrough openings 10a in one Wall of the chamber 1, Whichvopenings are suficiently large. to permit the introduction of a limitedquantity of oxygen to the chamber 1 during the distillation and heattreatment of the materials therein.

The pans as they reach the point are adapted to each receive preformedmasses a of coal and oil of a plastic consistency or masses ofy coalWith any suitable binder. These masses may be shaped in a moldingmachine or other suitable type of apparatus. They are placed in the pan7 as the pans enter the retort 1. The fuel masses are heated duringpassage through the retort by heat imparted thereto by heat storageelements 10. These elements are composed of cast iron or' other materialcapable of absorbing heat and are heated in a furnace exteriorly of theoven 1. They are inserted vin the pockets 9 formed in each pan'at thepoint and travel With the pans through the carbonizing zone 1, applyingheat to the preformed masses` in the pans duringthis travel. As shown inFig. 3, the pans need not have the false bottom 8. 1n this operation theheat storing elements 10 rest on the bottoms of the pans and thepreformed masses seat directly on these elements.

When a pan reaches the point m the cool heat storing member 10 isremoved and a heated element substituted in its place. One or more ofthe preformed masses a are then placed in the pan. storing elementpasses on through the carbonizing retort undergoing a low temperaturecarbonizing treatment therein in the presenceY of oxygen entering theretort through the openings 10a. lln this operation the `heat storingelements 10 are preferably heated to a temperature sucient to impart tothe preformed-fuel masses a temperature of from 450 to 575 F. The speedofthe conveyor through the retort. is regulated so'that it will requirefrom 45 minutes to 1 hour 30 minutes for apan with its material totravel through the retort to the 'llhe pan with its heat asf the openingof the valve 20.

sprocket 2. rlhis temperature and time of treatment is followed whenusing a non-coking coal. If a highly coking coal is used, substantiallythe same temperatures are employed but the time of treatment must belonger. This time of treatment Will vary from one and one-half hours tofour hours. The coal thus treated Will be hardened or carbonized aroundits surface but Will not be coked. vrl`he fuel masses may be said to beno more than case-hardened by this treatmerit, and of course, asubstantial quantity of the lighter volatiles is removed.

After treatment in the retort 1 the casehardened fuel masses are droppedinto the trough 11 and discharged through the outlet line 12 on to aconveyor 13, the empty receivers passing on back to the point Where newheat storage elements are inserted and Where fresh charges of fuel areplaced in the receivers.

lThe foregoing treatment constitutes the the first-stage treatment ofthe fuel.

r1`he case-hardened masses depositing on the belt 13 are then led bythis belt to a suitable retort 14 Where said masses are subjected to aconsiderably higher temperature to undergo a higher degree carbonizationtherein. Various forms of retorts can be used for this purpose but forthe sake of illustrating the invention l have disclosed a vertical shaleretort. rllhis retort has an outer insulated Wall 15 and an inner spacedWall 1o. rlhe lovver part of the Wall 16 is lined With hre clay 17 Whilethe upper portion thereof consists merely of steel or iron, there beinga space 18 between the Walls. rfhe carbonized fuel masses carried by thebelt 13 are discharged into the hopper 19 at the top of the retort andpermitted to enter the retort by These masses fill the retort which hasits lower end closed by a belt 21 movable over pulleys 22. Gas burners23 enter the space 18 between the Walls of the retort, producing a damethat is projected against the Wall 16 of the retort, raising thetemperature thereof to the desired degree. l preferably heat thecarboni'zed vmasses in the retort at a temperature of from 1100 to 1200oF. This maximum temperature is/attaine'd near the lower part of theretort. Little or no air is present in the interior of the retortcontaining the preformed fuel masses 24 Which are undergoing heattreatment therein, and l have discovered that when these masses aretreated in this retort under 'the temperatures mentioned in the absenceof air, that the casehardened masses will carbonize or coke Withoutswelling. That is to say, the carbonized fuel thus produced'is in 'theform of preformed masses of the .saine dimensions as the dimensions ofthe green fuel charges a introduced to the preheating or case-hardeningretort 1. There is no swelling nor Warme prevent over-heating of thebrick Wall 1'? of the Wall 16 and tol distribute heat throughout theretort.

The bottom Walls of the retort are slightly cut away as indicated by thereference character 27 and as the fuel masses reach the bottom of theretortthe conveyor 21 is moved to carry out of the retort those massesthat have been suihciently treated. Such masses are led to a pointofcollectioii.

ln treating the case-hardened masses in the final retort l preferablysubject such masses to a treatment of from 45 minutes to one andone-half hours, and as before stated, heat the carbonized masses to atemperature of from 1100 to 1200 F. This, l have found, causes acomplete carbonization or coking of the fuel charges Without causingthese charges to swell or become distorted. 1t will also be observedthat this high tem.-

perature treatment should be carried out in an atmosphere in whichlittle or no oxygen is present.

lt is believed from the foregoing that the operation of this process/isy apparent but it may be briefly repeated as follows:

Fuel masses formed in a molding maehine, press or the like, of anydesired contour, are

placed in the pans 7 which also carry the heat absorbing elements 10.These fuel masses a pass through 4the low temperature oven 1 and undergopartial carbonization in the presence of oxygen admitted to said retortthrough the openings 10% rlhis treatment causes a case-hardening orpartial carbonization of the fuel masses. 'fhe'y are discharged from thecontainers as the containers pass around the sprockets 2, aredeposited Yon the belt 13 and led to the high temperature retort 14. ln this retort1d a temperature of from 1100 to 1200o F. is maintained' as comparedWith the comparatively low temperature of from 450 to 575C in theretort 1. Little or no oxygen vis permitted to enter the retort 14 andthe coking or carbonizing of the partially carbonized masses enteringthis retort is carried on in the absence of an oxidizing atmosphere. A.definite time of treatment must be maintained in the lovv temperatureretort 1 and also in the high temperature retort 14C. These periods oftreatment have heretofore been set forth.

The fuel masses discharging from the retort to an increased temperaturein ainal heat- 14 are substantially completely carbonized ing zone tocomplete carbonlzation thereof and these masses are neither swollen norhas While excludlng air from said zone.

there been any substantial shrinkage as compared with the original fuelmasses w. The carbonized product recovered is of dimensionssubstantially the sameas the dimensions of the green fuel charges fromwhich the product is made. -These fuel charges are carried from theretort 14 by the belt 21 trained around pulleys 22 and deposited in asuitable storage space or container not shown. i

Having thus described the invention, what I claim is:

1. A carbonizing process, ,consisting in applying preformed masses ofcarbonaceous., material of at least plastic consistency to a receiver,in disposing in heat conductlve relation with said masses heat storageelements,

in moving the fuel masses and heat storage elements through a retortwhere the fuel masses are heated to a temperature in the presence of airsufficient to partially carbonize the same, in then `transferring thepartially carbonized .fuel masses to a second retort, and in subjectingsaid masses in said retort to a substantiallyv increasedtemperaturewhile in an atmosphere largely free of p oxygen for such timeas t0 completely carbonize the fuclmasses Without'causing diss tortionor shrinkage thereof.

2. A process for carbonizing preformed masses of carbonaceous materialof at least plastic consistency, consisting in preliminarily introducingsaid masses to a heating zone, in there heating the masses to atemperature suilicient to cause only partial carbonization thereof Whilepermitting a free unobstructed entrance of air`to said preliminaryheating zone, in introducing the partially carbonized fuel masses to anal heating zone, in subjecting said masses in said zone to asubstantially higher temperature for such time as to completelycarbonize the fuel lmasses Without `causing distortion or shrinkagethereof While substantially excluding air from said final heating zone,the initial heat treatment of the fuel masses being characterized by theapplication of heat to said masses transmitted thereto by heat storageelements containing sutlicient heatto partially carbonize said masses.

'3. A process of carbonizing preformed masses of carbonaceous materialof at least plastic consistency consisting in introducing said preformedmasses to a preliminar heating zone, in moving said masses throug saidzone while positioned adjacent heat storage means havingstorage capacitysuiii- Icient to' partially carbonize said masses by the contained heatthereof, in permittingal free admission of air through said zone durlngthe carbonizatlon of materials therein,

in subjecting the partially carbonized masses In testimony whereof Iaffix my signature.

WALTER EDWIN TRENT.

